Faslane Naval Base, situated on the Gare Loch, and the RN Armaments Depot Coulport on Loch Long, are the primary components of HMNB Clyde. The naval shore establishment at Faslane is HMS Neptune, Naval personnel appointed to the base who do not belong to a seagoing vessel make up Ship's Company. Both the Gare Loch and Loch Long are sea lochs extending northwards from the Firth of Clyde. The base serves as home base to Britain's fleet of Vanguard-class nuclear-powered and nuclear-armed submarines, as well as conventionally armed nuclear-powered submarines, supported by the Fleet Protection Group Royal Marines.

In command of HMNB Clyde is the Naval Base Commander (Clyde), Commodore C J Hockley who succeeded Commodore Carolyn Stait in Autumn 2007.[6] The base is home to a number of lodger units including Flag Officer Scotland, Northern England and Northern Ireland (FOSNNI) (who is also Flag Officer Reserves/FORes), the Northern Diving Group and the Scottish Headquarters of the Ministry of Defence Police and Guarding Agency. It is base to 3,000 service personnel, 800 of their families and 4,000 civilian workers, largely from Babcock Marine, forming a major part of the economy of Argyll and Bute and West Dunbartonshire.

Faslane itself was chosen to host these vessels at the height of the Cold War because of its geographic position, which forms a bastion on the relatively secluded but deep and easily navigable Gare Loch and Firth of Clyde on the west coast of Scotland. This position provides for rapid and stealthy access through the North Channel to the submarine patrolling areas in the North Atlantic, through the GIUK gap to the Norwegian Sea. At the time is was chosen, the location was also close to the American SSBN base at Holy Loch, which operated 1961-1992. One boat was always on patrol at any given time. In times of political instability, sometimes two boats would be deployed at sea.

In 1971 the base was home to the 3rd Submarine Squadron of Nuclear Fleet and Diesel Patrol Submarines, “the fighters”, and the 10th Submarine Squadron consisting of the four Polaris submarines, “the bombers”.[7] The base also conducted the training of all submarines before they joined their Squadrons and this was known as ‘work up’.

Exercise Evening Star is the annual test of the emergency response routines to a nuclear weapon accident at Faslane. It is conducted by the Office for Nuclear Regulation. In 2011 the test failed as "a number of command and control aspects of the exercise were not considered to have been adequately demonstrated".[11]

In 2013-14 there were 99 radiation accidents concerning nuclear reactors, and 6 with nuclear weapons. These are the highest numbers for at least six years. The MoD maintains that there was no risk to the public as most of them were minor accidents. The SNP defence spokesman, Angus Robertson, called the figures "totally shocking".[12]

The Scottish National Party, the Scottish Socialist Party, and the Scottish Green Party all oppose the deployment of nuclear weapons, although the Scottish National Party have made assurances that they would retain the base for the servicing of conventionally armed and conventionally powered naval units. It is not unusual for members of these parties, and indeed some from the Labour Party to be present. Also, some independents, such as George Galloway attend rallies outside Faslane. Such events aim to keep the base closed for as long as possible by preventing its staff from arriving for work, and usually involve large numbers of protesters being arrested for non-violent civil disobedience.

The "big blockade" at Faslane Naval Base is an annual event held since 1999 usually in the 2nd week of February, aiming to close the base for 24 hours (although never successfully). The event attracts thousands of peace activists and has on occasion resulted in more than 350 arrests.

Police dismantling a blockade of protesters from York at the south gate of the Faslane base

The Faslane 365 campaign was a one-year protest at the base. It was a civil resistance initiative to apply critical public pressure for the disarmament of Britain's nuclear weapons.[13]

The campaign was launched in September 2006 with the first protest action commencing on 1 October 2006 carried out by a campaigning group of women associated with protests at Greenham Common. It formally ended with a Big Blockade on 1 October 2007. However, groups are continuing to take direct action at both Faslane and Coulport.

131 blockading groups took part in Faslane 365 and 1150 arrests were made.[13]

The Royal Naval Armaments Depot (RNAD) at Coulport, Loch Long is the other major part of HMNB Clyde. RNAD Coulport stores conventional armaments for Royal Navy vessels but is best known for its role in the Trident missile system.

Nuclear weapon storage bunkers have been excavated from a ridge. British-designed and built nuclear warheads, can be fitted to Trident missiles (built by Lockheed Martin). The United Kingdom has ownership rights to 58 missiles from a "pool" shared with the U.S. Navy. Whole missiles can be lifted out of or into a submarine, but the missiles are normally serviced at the U.S. Navy facility at Naval Submarine Base Kings Bay in the U.S. state of Georgia.

Initial construction took place between 1963, when Faslane was chosen as the new Polaris base, and 1968, when the first Polaris boat began its patrol. Safety considerations required that the armament maintenance and storage facility have its own berth and be at least 4,400 feet (1,300 m) from the main facility, whilst operational considerations dictated that the two facilities should be within an hour's sailing time. Coulport, on the opposite peninsula, met both of these requirements.[14] Additional construction took place during the 1980s to support the Trident missile programme.